Donepezil



Better Known as: Aricept

 * Marketed By: Eisai & Pfizer


 * Major Indication: Alzheimer's Disease


 * Drug Class: Acetylcholinesterase Inhibitor
 * Date of FDA Approval (Patent Expiration): 1996 (2008)


 * 2006 Sales: $1.4 Billion
 * Importance: One of the most effective treatments for the symptoms of Alzheimer's Disease, although no definitive proof exists as to whether it alters the progression of the disease.
 * See: Pharmaceutical Drugs for more information about other drugs and disorders

Mechanism of Action
Donepezil is a potent Acetylcholinesterase (AChE) inhibitor to the active site of AChE. By inhibiting AChE, the important neurotransmitter, acetylcholine, is degraded at a slower rate, helping reverse the marked decrease in neuronal function evident in Alzheimer's Disease patients. Donepezil binds along the active-site gorge, extending from the anionic subsite near Trp 84 to the peripheral anionic site near Trp 279. Interestingly, it does not directly interact with the catalytic triad of acetylcholinesterase nor the oxyanion hole. Further, donepezil does not form any direct hydrogen bonds with AChE nor electrostatic interactions, but rather only interacts via aromatic stacking and solvent mediated interactions. It primarily interacts with Glu 199, His 440, Phe 330, Trp 84, Tyr 334, Tyr 121, Phe 331, Phe 288, Ser 286, Phe 290, Arg 289, Trp 279, & Leu 282 to tightly bind to AChE.